National Semiconductor LM317A, LM317 Technical data
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LM117/LM317A/LM317
3-Terminal Adjustable Regulator
General Description
The LM117 series of adjustable 3-terminal positive voltage
regulators is capable of supplying in excess of 1.5A over a
1.2V to 37V output range. They are exceptionally easy to
use and require only two external resistors to set the output
voltage. Further, both line and load regulation are better than
standard fixed regulators. Also, the LM117 is packaged in
standard transistor packages which are easily mounted and
handled.
In addition to higher performance than fixed regulators, the
LM117 series offers full overload protection available only in
IC’s. Included on the chip are current limit, thermal overload
protection and safe area protection. All overload protection
circuitry remains fully functional even if the adjustment terminal is disconnected.
Normally, no capacitors are needed unless the device is
situated more than 6 inches from the input filter capacitors in
which case an input bypass is needed. An optional output
capacitor can be added to improve transient response. The
adjustment terminal can be bypassed to achieve very high
ripple rejection ratios which are difficult to achieve with standard 3-terminal regulators.
Besides replacing fixed regulators, the LM117 is useful in a
wide variety of other applications. Since the regulator is
“floating” and sees only the input-to-output differential volt-
July 2004
age, supplies of several hundred volts can be regulated as
long as the maximum input to output differential is not exceeded, i.e., avoid short-circuiting the output.
Also, it makes an especially simple adjustable switching
regulator, a programmable output regulator, or by connecting
a fixed resistor between the adjustment pin and output, the
LM117 can be used as a precision current regulator. Supplies with electronic shutdown can be achieved by clamping
the adjustment terminal to ground which programs the output to 1.2V where most loads draw little current.
For applications requiring greater output current, see LM150
series (3A) and LM138 series (5A) data sheets. For the
negative complement, see LM137 series data sheet.
Features
n Guaranteed 1% output voltage tolerance (LM317A)
n Guaranteed max. 0.01%/V line regulation (LM317A)
n Guaranteed max. 0.3% load regulation (LM117)
n Guaranteed 1.5A output current
n Adjustable output down to 1.2V
n Current limit constant with temperature
+
n P
Product Enhancement tested
n 80 dB ripple rejection
n Output is short-circuit protected
LM117/LM317A/LM317 3-Terminal Adjustable Regulator
Typical Applications
1.2V–25V Adjustable Regulator
Full output current not available at high input-output voltages
*
Needed if device is more than 6 inches from filter capacitors.
†
Optional —improves transient response. Output capacitors in the range
of 1µF to 1000µF of aluminum or tantalum electrolytic are commonly used
to provide improved output impedance and rejection of transients.
00906301
LM117 Series Packages
Part Number Design
Suffix Package Load
Current
K TO-3 1.5A
H TO-39 0.5A
T TO-220 1.5A
E LCC 0.5A
S TO-263 1.5A
EMP SOT-223 1A
MDT TO-252 0.5A
SOT-223 vs. D-Pak (TO-252)
Packages
00906354
Scale 1:1
© 2004 National Semiconductor Corporation DS009063 www.national.com
Connection Diagrams
LM117/LM317A/LM317
CASE IS OUTPUT
NS Package Number K02A or K02C
(TO-263) Surface-Mount Package
(TO-3)
Metal Can Package
Bottom View
Steel Package
Top View
00906330
(TO-39)
Metal Can Package
00906331
CASE IS OUTPUT
Bottom View
NS Package Number H03A
(TO-220)
Plastic Package
00906335
Side View
00906336
NS Package Number TS3B
Front View
00906332
NS Package Number T03B
Ceramic Leadless
Chip Carrier
00906334
Top View
NS Package Number E20A
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Connection Diagrams (Continued)
4-Lead SOT-223 TO-252 (D-Pak)
LM117/LM317A/LM317
Front View
00906359
NS Package Number MP04A
Front View
00906366
NS Package Number TD03B
Ordering Information
Package Temperature Range Part Number Package Marking Transport Media NSC
Drawing
Metal Can
(TO-3)
−55˚C ≤ T
0˚C ≤ T
−55˚C ≤ T
Metal Can
(TO-39)
−55˚C ≤ T
−55˚C ≤ T
−40˚C ≤ T
0˚C ≤ T
TO-220
3- Lead
TO-263
−40˚C ≤ T
0˚C ≤ T
0˚C ≤ T
3- Lead
LCC −55˚C ≤ T
SOT-223
0˚C ≤ T
4- Lead
−40˚C ≤ T
D- Pack
0˚C ≤ T
3- Lead
−40˚C ≤ T
≤ +150˚C LM117K STEEL LM117K STEEL P+ 50 Per Bag K02A
J
≤ +125˚C LM317K STEEL LM317K STEEL P+ 50 Per Bag
J
≤ +150˚C LM117K/883 LM117K/883 50 Per Bag K02C
J
≤ +150˚C LM117H LM117H P+ 500 Per Box H03A
J
≤ +150˚C LM117H/883 LM117H/883 20 Per Tray
J
≤ +125˚C LM317AH LM317AH P+ 500 Per Box
J
≤ +125˚C LM317H LM317H P+ 500 Per Box
J
≤ +125˚C LM317AT LM317AT P+ 45 Units/Rail T03B
J
≤ +125˚C LM317T LM317T P+ 45 Units/Rail
J
≤ +125˚C LM317S LM317S P+ 45 Units/Rail TS3B
J
LM317SX 500 Units Tape and Reel
≤ +150˚C LM117E/883 LM117E/883 50 Units/Rail E20A
J
≤ +125˚C LM317EMP N01A 1k Units Tape and Reel MP04A
J
LM317EMPX 2k Units Tape and Reel
≤ +125˚C LM317AEMP N07A 1k Units Tape and Reel
J
LM317AEMPX 2k Units Tape and Reel
≤ +125˚C LM317MDT LM317MDT 75 Units/Rail TD03B
J
LM317MDTX 2.5k Units Tape and Reel
≤ +125˚C LM317AMDT LM317AMDT 75 Units/Rail
J
LM317AMDTX 2.5k Units Tape and Reel
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Absolute Maximum Ratings (Note 1)
ESD Tolerance (Note 5) 3 kV
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Power Dissipation Internally Limited
Input-Output Voltage Differential +40V, −0.3V
Storage Temperature −65˚C to +150˚C
LM117/LM317A/LM317
Lead Temperature
Metal Package (Soldering, 10 seconds) 300˚C
Plastic Package (Soldering, 4 seconds) 260˚C
Operating Temperature Range
LM117 −55˚C ≤ TJ≤ +150˚C
LM317A −40˚C ≤ T
LM317 0˚C ≤ T
Preconditioning
Thermal Limit Burn-In All Devices 100%
J
J
Electrical Characteristics (Note 3)
Specifications with standard type face are for TJ= 25˚C, and those with boldface type apply over full Operating Temperature Range. Unless otherwise specified, V
IN−VOUT
= 5V, and I
Parameter Conditions LM117 (Note 2) Units
Reference Voltage V
3V ≤ (V
IN−VOUT
10 mA ≤ I
Line Regulation 3V ≤ (VIN−V
Load Regulation 10 mA ≤ I
) ≤ 40V, 1.20 1.25 1.30 V
≤ I
OUT
OUT
,P≤ P
MAX
) ≤ 40V (Note 4) 0.01 0.02 %/V
OUT
≤ I
(Note 4) 0.1 0.3 %
MAX
Thermal Regulation 20 ms Pulse 0.03 0.07 %/W
Adjustment Pin Current 50 100 µA
Adjustment Pin Current Change 10 mA ≤ I
3V ≤ (V
Temperature Stability T
Minimum Load Current (V
Current Limit (V
≤ TJ≤ T
MIN
IN−VOUT
IN−VOUT
≤ I
OUT
MAX
IN−VOUT
) ≤ 40V
MAX
) = 40V 3.5 5 mA
) ≤ 15V
K Package 1.5 2.2 3.4 A
H Package 0.5 0.8 1.8 A
(V
IN−VOUT
) = 40V
K Package 0.3 0.4 A
H Package 0.15 0.2 A
RMS Output Noise, % of V
OUT
Ripple Rejection Ratio V
Long-Term Stability T
10 Hz ≤ f ≤ 10 kHz 0.003 %
= 10V, f = 120 Hz, 65 dB
OUT
C
=0µF
ADJ
V
= 10V, f = 120 Hz, 66 80 dB
OUT
C
=10µF
ADJ
= 125˚C, 1000 hrs 0.3 1 %
J
Thermal Resistance, K Package 2.3 3 ˚C/W
Junction-to-Case H Package 12 15 ˚C/W
E Package ˚C/W
Thermal Resistance, Junction- K Package 35 ˚C/W
to-Ambient (No Heat Sink) H Package 140 ˚C/W
E Package ˚C/W
OUT
MAX
= 10 mA.
Min Typ Max
0.02 0.05 %/V
0.3 1 %
0.2 5 µA
1 %
≤ +125˚C
≤ +125˚C
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Electrical Characteristics (Note 3)
Specifications with standard type face are for TJ= 25˚C, and those with boldface type apply over full Operating Temperature Range. Unless otherwise specified, V
IN−VOUT
= 5V, and I
Parameter Conditions LM317A LM317 Units
Reference Voltage 1.238 1.250 1.262 V
3V ≤ (V
IN−VOUT
10 mA ≤ I
Line Regulation 3V ≤ (VIN−V
Load Regulation 10 mA ≤ I
) ≤ 40V, 1.225 1.250 1.270 1.20 1.25 1.30 V
≤ I
OUT
OUT
,P≤ P
MAX
) ≤ 40V (Note 4) 0.005 0.01 0.01 0.04 %/V
OUT
≤ I
MAX
MAX
(Note 4) 0.1 0.5 0.1 0.5 %
Thermal Regulation 20 ms Pulse 0.04 0.07 0.04 0.07 %/W
Adjustment Pin Current 50 100 50 100 µA
Adjustment Pin Current
Change
Temperature Stability T
Minimum Load Current (V
Current Limit (V
10 mA ≤ I
3V ≤ (V
IN−VOUT
≤ TJ≤ T
MIN
IN−VOUT
IN−VOUT
≤ I
OUT
MAX
) ≤ 40V
MAX
) = 40V 3.5 10 3.5 10 mA
) ≤ 15V
K, T, S Packages 1.5 2.2 3.4 1.5 2.2 3.4 A
H Package
MP Package
(V
IN−VOUT
) = 40V
K, T, S Packages 0.15 0.4 0.15 0.4 A
H Package
MP Package
RMS Output Noise, % of V
Ripple Rejection Ratio V
Long-Term Stability T
Thermal Resistance,
Junction-to-Case
10 Hz ≤ f ≤ 10 kHz 0.003 0.003 %
OUT
= 10V, f = 120 Hz, 65 65 dB
OUT
C
=0µF
ADJ
V
= 10V, f = 120 Hz, 66 80 66 80 dB
OUT
C
=10µF
ADJ
= 125˚C, 1000 hrs 0.3 1 0.3 1 %
J
K Package
MDT Package
H Package 12 15 12 15 ˚C/W
T Package
MP Package
Thermal Resistance,
Junction-to-Ambient (No Heat
Sink)
K Package
MDT Package(Note 6)
H Package 140 140 ˚C/W
T Package 50 50 ˚C/W
S Package (Note 6) 50 50 ˚C/W
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The
guaranteed specifications apply only for the test conditions listed.
Note 2: Refer to RETS117H drawing for the LM117H, or the RETS117K for the LM117K military specifications.
Note 3: Although power dissipation is internally limited, these specifications are applicable for maximum power dissipations of 2W for the TO-39 and SOT-223 and
20W for the TO-3, TO-220, and TO-263. I
All limits (i.e., the numbers in the Min. and Max. columns) are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 4: Regulation is measured at a constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are
covered under the specifications for thermal regulation.
Note 5: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 6: If the TO-263 or TO-252 packages are used, the thermal resistance can be reduced by increasing the PC board copper area thermally connected to the
package. Using 0.5 square inches of copper area. θ
area, θ
is 32˚C/W. If the SOT-223 package is used, the thermal resistance can be reduced by increasing the PC board copper area (see applications hints for
JA
heatsinking).
is 1.5A for the TO-3, TO-220, and TO-263 packages, 0.5A for the TO-39 package and 1A for the SOT-223 Package.
MAX
is 50˚C/W; with 1 square inch of copper area, θJAis 37˚C/W; and with 1.6 or more square inches of copper
JA
OUT
= 10 mA.
Min Typ Max Min Typ Max
0.01 0.02 0.02 0.07 %/V
0.3 1 0.3 1.5 %
0.2 5 0.2 5 µA
11%
0.5
1.5
0.075
0.15
0.8
2.2
0.2
0.4
1.8
3.4
0.5
1.5
0.075
0.15
0.8
2.2
0.2
0.4
2.3
5
4
23.5
54
23.5
35 35
92
1.8
3.4
3 ˚C/W
˚C/W
˚C/W
˚C/W
˚C/W
˚C/W
A
A
A
A
LM117/LM317A/LM317
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Typical Performance Characteristics Output Capacitor = 0µF unless otherwise noted
Load Regulation Current Limit
LM117/LM317A/LM317
00906337
Adjustment Current Dropout Voltage
00906339
Temperature Stability Minimum Operating Current
00906338
00906340
00906341
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00906342
Typical Performance Characteristics Output Capacitor = 0µF unless otherwise noted (Continued)
Ripple Rejection Ripple Rejection
LM117/LM317A/LM317
00906343
Ripple Rejection Output Impedance
00906345
Line Transient Response Load Transient Response
00906344
00906346
00906347 00906348
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Application Hints
In operation, the LM117 develops a nominal 1.25V reference
voltage, V
The reference voltage is impressed across program resistor
R1 and, since the voltage is constant, a constant current I
then flows through the output set resistor R2, giving an
output voltage of
LM117/LM317A/LM317
, between the output and adjustment terminal.
REF
00906305
can cause excessive ringing. This occurs with values between 500 pF and 5000 pF. A 1µF solid tantalum (or 25µF
aluminum electrolytic) on the output swamps this effect and
insures stability. Any increase of the load capacitance larger
than 10µF will merely improve the loop stability and output
1
impedance.
LOAD REGULATION
The LM117 is capable of providing extremely good load
regulation but a few precautions are needed to obtain maximum performance. The current set resistor connected between the adjustment terminal and the output terminal (usually 240Ω) should be tied directly to the output (case) of the
regulator rather than near the load. This eliminates line
drops from appearing effectively in series with the reference
and degrading regulation. For example, a 15V regulator with
0.05Ω resistance between the regulator and load will have a
load regulation due to line resistance of 0.05Ω xI
. If the set
L
resistor is connected near the load the effective line resistance will be 0.05Ω (1 + R2/R1) or in this case, 11.5 times
worse.
Figure 2 shows the effect of resistance between the regulator and 240Ω set resistor.
FIGURE 1.
Since the 100µA current from the adjustment terminal represents an error term, the LM117 was designed to minimize
and make it very constant with line and load changes.
I
ADJ
To do this, all quiescent operating current is returned to the
output establishing a minimum load current requirement. If
there is insufficient load on the output, the output will rise.
EXTERNAL CAPACITORS
An input bypass capacitor is recommended. A 0.1µF disc or
1µF solid tantalum on the input is suitable input bypassing
for almost all applications. The device is more sensitive to
the absence of input bypassing when adjustment or output
capacitors are used but the above values will eliminate the
possibility of problems.
The adjustment terminal can be bypassed to ground on the
LM117 to improve ripple rejection. This bypass capacitor
prevents ripple from being amplified as the output voltage is
increased. With a 10µF bypass capacitor 80dB ripple rejection is obtainable at any output level. Increases over 10µF do
not appreciably improve the ripple rejection at frequencies
above 120Hz. If the bypass capacitor is used, it is sometimes necessary to include protection diodes to prevent the
capacitor from discharging through internal low current paths
and damaging the device.
In general, the best type of capacitors to use is solid tantalum. Solid tantalum capacitors have low impedance even at
high frequencies. Depending upon capacitor construction, it
takes about 25µF in aluminum electrolytic to equal 1µF solid
tantalum at high frequencies. Ceramic capacitors are also
good at high frequencies; but some types have a large
decrease in capacitance at frequencies around 0.5MHz. For
this reason, 0.01µF disc may seem to work better than a
0.1µF disc as a bypass.
Although the LM117 is stable with no output capacitors, like
any feedback circuit, certain values of external capacitance
00906306
FIGURE 2. Regulator with Line Resistance in Output
Lead
With the TO-3 package, it is easy to minimize the resistance
from the case to the set resistor, by using two separate leads
to the case. However, with the TO-39 package, care should
be taken to minimize the wire length of the output lead. The
ground of R2 can be returned near the ground of the load to
provide remote ground sensing and improve load regulation.
PROTECTION DIODES
When external capacitors are used with any IC regulator it is
sometimes necessary to add protection diodes to prevent
the capacitors from discharging through low current points
into the regulator. Most 10µF capacitors have low enough
internal series resistance to deliver 20A spikes when
shorted. Although the surge is short, there is enough energy
to damage parts of the IC.
When an output capacitor is connected to a regulator and
the input is shorted, the output capacitor will discharge into
the output of the regulator. The discharge current depends
on the value of the capacitor, the output voltage of the
regulator, and the rate of decrease of V
. In the LM117, this
IN
discharge path is through a large junction that is able to
sustain 15A surge with no problem. This is not true of other
types of positive regulators. For output capacitors of 25µF or
less, there is no need to use diodes.
The bypass capacitor on the adjustment terminal can discharge through a low current junction. Discharge occurs
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